A Theory About Rising pH in SWG Pools

[chem geek]

Limestone is primarily calcite which is calcium carbonate, the same major component that is used in the production of cement that is in plaster/gunite/grout so the same rules for water balance apply. I don't believe the issue of corrosion vs. scaling will be any different for limestone than for the plaster/gunite/grout except perhaps that the limestone may be more sensitive to this chemical balance since it is much more "pure" calcium carbonate (i.e. doesn't have its calcium carbonate converted to calcium oxide bound to silicon oxide in cement though the aggregate in concrete is often limestone).

So I wouldn't expect a change in pH from the limestone unless your water was out of balance. If your water was too low in TA, pH and/or CH, then you could corrode the calcium carbonate from the limestone and that would slightly increase your CH and TA and would increase your pH.

Richard